Smartphone Audio Quality Testingby Chris Heinonen on December 8, 2013 5:15 PM EST
Right now we have full data on four phones and partial data on a few more. We are working to compile as much data as possible to provide an overall look at the quality of audio from smartphones available today. The largest difference in current models is the power of the headphone output as some are much better equipped to drive more demanding headphones than others. As we compile data on more and more products we hope to see more differences arise.
We also have not seen much difference with different loads applied to the headphones. We will continue to test all three sets of headphones but the data here is for the Apple Earbuds. If different loads provide different results, then we will certainly report those different numbers in the future. It also appears that running Android phones in the automated routine causes the 20 kHz tone to be left out of the frequency response test. Humans usually can't hear this, I certainly can't, and so there isn't a huge amount of real-world ramification to this. It causes the reported THD+N to exclude that tone and provides a better result that phones that play it back. For the future, this will be done manually.
Here are the four phones we currently have, and more phones are being tested and reported on as quickly as possible to be added here.